Abstract Despite the experimentation of bainitic and martensitic microstructures in wheel-rail steels, pearlitic microstructure remains dominant in railway track. The wear resistance behavior of bainitic and pearlitic microstructures is still a matter of controversy. In this study, pin-on-disc sliding wear tests were performed to analyze the effects of the microstructure on wear resistance. The AISI 1080 steel was isothermally treated at five temperatures using a dilatometer in order to obtain pearlite, bainite and martensite structures. After these treatments, bainitic and martensitic samples were tempered at 500°C. It was possible to achieve pearlitic specimens with interlamellar spacing ranging from 70 ± 4 nm to 243 ± 9 nm. It was found that the wear resistance increases with decreasing the interlamellar spacing, fine pearlite showed 30% lower mass loss than coarse pearlite. The severe deformation and dislocation accumulation in different depth from the contact surface were analyzed by electron backscattered diffraction technique. The results showed that the first 10 µm depth from the contact surface was severely deformed and a high number of random high-angle boundaries developed due to the large compressive force. Fine pearlitic structure tends to present a better wear performance when compared to bainitic or martensitic structures.

Derived from flexibility matrix, Uniform Load Surface (ULS) is used to identify damages in beam-type structures. This method is beneficial in terms of more participating the lower order modes and having less prone to noise and irregularities in the measured data in comparison with the original flexibility matrix technique. Therefore, these characteristics make this approach a practical tool in the field of damage identification. This paper presents a procedure to employ stationary wavelet transform multi-resolution analysis (SWT-MRA) to refine ULS obtained from the damaged structure and then using continuous wavelet transform (CWT) for localizing the discontinuity of improved ULS as a sign of damage site. Evaluation of the proposed method is carried out by examining a cantilever beam as a numerical case, where the ULS is formed by using mode shapes of damaged beam and two kinds of wavelets (i.e. symmetrical 4 and bior 6.8) is applied for discerning the induced crack. Moreover, a laboratory test is conducted on a free-free beam to experimentally evaluate the practicability of the technique.